1. What is 3-Phase MVA?

MVA (Mega Volt-Ampere) is a unit of apparent power in three-phase electrical systems. It represents the total power in a system, combining both real (kW) and reactive (kVAR) power components.

2. How Does the Calculator Work?

The calculator uses the 3-phase MVA formula:

Where:

• \( kV \) — Line-to-line voltage in kilovolts
• \( Amps \) — Current in amperes
• \( \sqrt{3} \) — Constant for 3-phase systems (≈1.732)
• 1000 — Conversion factor to get MVA

Explanation: The formula calculates the apparent power in a balanced three-phase system by accounting for the phase difference between voltage and current.

3. Importance of MVA Calculation

Details: MVA is crucial for sizing electrical equipment, determining system capacity, and analyzing power system performance. It's used by engineers for transformer sizing, circuit breaker selection, and power system design.

4. Using the Calculator

Tips: Enter line-to-line voltage in kV and current in amps. Both values must be positive numbers. The calculator assumes a balanced three-phase system.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between MVA and MW?
A: MVA is apparent power (including both real and reactive power), while MW is real power. MW = MVA × power factor.

Q2: Why use √3 in the formula?
A: The √3 accounts for the phase difference in three-phase systems, converting line-to-line voltage to phase voltage.

Q3: Is this formula valid for single-phase systems?
A: No, for single-phase use MVA = (kV × Amps)/1000 (without the √3 factor).

Q4: What are typical MVA ratings for equipment?
A: Transformers might be 10 MVA, 30 MVA, etc. Large generators can be hundreds of MVA.

Q5: How does power factor affect MVA?
A: Power factor doesn't change MVA (apparent power) but affects the ratio of real power (MW) to reactive power (MVAR).